The present invention is directed to an apparatus and a method for collecting and processing specimens of biological fluid, including collecting uniform layers of cells therefrom suitable for use in cytology protocols.
In a wide variety of technologies, the ability and/or facility in separating matter, typically particulate matter, from a fluid is a critical component in the ability to test for the presence of substances in the fluid. Too often, interference associated with sample preparation obscures the target particles to such a degree that the process is not sufficiently reliable, or too costly. Such problems exist in various fields of examination which involve detection and/or diagnosis, including environmental testing, radiation research, cancer screening through cytological examination, microbiological testing, and hazardous waste contamination, to name just a few.
Cytological examination of a sample begins with obtaining specimens including a sample of cells from the patient, which can typically be done by scraping or swabbing an area, as in the case of cervical samples, or by collecting body fluids, such as those obtained from the chest cavity, bladder, or spinal column, or by fine needle aspiration or fine needle biopsy. In a conventional manual cytological preparation, the cells in the fluid are then transferred directly onto a glass slide for viewing. In a conventional automated cytological preparation, a filter assembly is placed in the liquid suspension and the filter assembly both disperses the cells and captures the cells on the filter. The filter is then removed and placed in contact with a microscope slide.
In all of these endeavors, a limiting factor in the sample preparation protocol is adequately separating solid matter from its fluid carrier, and in easily and efficiently collecting and concentrating the solid matter in a form readily accessible to microscopic examination. Diagnostic microbiology and/or cytology, particularly in the area of clinical pathology, bases diagnoses on a microscopic examination of cells and other microscopic analyses. The accuracy of the diagnosis and the preparation of optimally interpretable specimens typically depends upon adequate sample preparation. In this regard the ideal specimen would consist of a monolayer of substantially evenly spaced cells. Newer methodologies such as immunocytochemistry and image analysis require preparations that are reproducible, fast, biohazard-free and inexpensive.
Currently, biological samples are collected for cytological examinations using special containers. These containers usually contain a preservative solution for preserving the cytology specimen during shipment from the collection site to the cytology laboratory. Further, cytology specimens collected from the body cavities using a swab, smear, spatula or brush are also preserved in special containers with fixatives (e.g., alcohol or acetone fixatives) prior to transferring cells onto the slide or membrane for staining or examination.
Specimen containers are known that allow a liquid-based biological specimen to be processed directly in the container so as to obtain a substantially uniform layer of cells on a collection site (in a filter housing defining a particulate matter separation chamber) that is associated with the container itself. See, for example, U.S. Pat. Nos. 5,301,685; 5,471,994; 6,296,764; and 6,309,362, all of which are incorporated herein by reference. However, these types of specimen containers require specially configured apertured covers and adapters therefor that are designed to mate with the filter housing, and with suction equipment (e.g., a syringe or a mechanized vacuum source) used to aspirate liquid from the container and draw it through the filter. Further, extraction of the filter so that it can be pressed against a microscope slide to transfer collected cells to the slide requires disassembly of the cooperating parts of the cover and/or adapters associated therewith. If the processing is done by automated equipment, special handling devices are required to carry out such disassembly. All of this complexity adds time and material and labor cost to the processing required prior to the actual cytology examination.